Stabilizer trim attachment for power boats

ABSTRACT

An attachment for a power boat which fits on the transom or stern of the boat and comprises a pair of trim tabs hinged at the transom and extending rearwardly therefrom, and which may be swung vertically simultaneously to different angular positions to trim the boat so that it operates at the proper attitude regardless of its loading. The tabs are so formed that they also bring about lateral stability as well as impart the proper attitude to the boat. Furthermore, the tabs are positively moved vertically up or down to their selected angular positions.

United States Patent Ellsworth J. Frey Logan, Ohio 815,404

Apr. 11, 1969 May 1 l, 1971 Star Tab, Inc. Logan, Ohio lnventor Appl.No. Filed Patented Assignee STABILIZER TRIM ATTACHMENT FOR POWER BOATS 1Claim, 4 Drawing Figs US. Cl. 114/665 Int. Cl 1363b 1/22 Field of Searchll4/66.5

Relerenoes Cited UNITED STATES-PATENTS v 5/ l 944 Parker l l4/66.5X

3,399,643. 9/1968 Benn ett 1 14/665 3,404,651 l0/l968 Jensen etal.ll4/66.5- 3,468,278 9/l969 Kercheval Primary Examiner-Andrew H. FarrellAttorney-Mahoney, Miller & Stebens An attachment for a power boat whichfits on the transom or stem of the boat and comprises a pair of trimtabs hinged at the transom and extending rearwardly therefrom, and whichmay be'swung vertically simultaneously to difi'erent angular positionsto trim the boat so that it operates at the proper attitude regardlessof its loading. The

- tabs are so formed that they also bring about lateral stability aswell as impart the proper attitude to the boat. Furthermore, the tabsare positively moved vertically up or down to their selected angularpositions.

PATENTEU-HAH I |97l 3577,534

'- sum 2 UP 2 I Tk ELLSWORTH J. FREY BY MAHONE )1 MILLER 8 RAMBO l N VENTOR.

1 STABILIZER TRIM ATTACHMENT FOR POWER BOATS BACKGROUND OF THE INVENTIONVarious trim tab attachments have been provided in the past forobtaining the proper attitude in the movement of the boats through thewater under various loaded conditions.

However, these prior art attachments have not included means forobtaining lateral stability. Also, the operating means for these tabshave not been positive in both directions to permit a definite selectionof angular position of the tabs. According to the present invention,lateral stability is accomplished as well as positive selection of theangular position of the tabs in order to obtain the desired attitude ofthe boat under various loaded conditions.

in the accompanying drawings, l have illustrated a preferred embodimentof my-invention and in these drawings:

FIG. 1 is a side elevational view of a portion of a boat at its stern,partly broken away, showing my attachment applied to the transomthereof.

FIG. 2 is a horizontal sectional view taken along line 2-2 of FIG. 1.

FIG. 3 is a rear view taken along line 3-3 of FIG. 1.

FIG. 4 is a schematic diagram of the hydraulic and electric controlcircuit for controlling the angular position of the trim With referenceto the drawings, 1 have shown in FIG. 1, the stern portion of a powerboat of the inboard motor type with the transom l and the bottom 11converging at a lower corner 12. The trim tabs of this invention areindicated generally at 13 and 14 and are hinged about a transverse axis,indicated at 15, for vertical swinging movement. This axis is adjacentthe corner 12. Y

The tabs 13 and 14 are hinged side by side, but with a space 16therebetween. If the attachment is used on an outboard motor type boatthis spacing could be increased if necessary. Each tab is made ofrelatively stiff sheet metal with a straight forward edge which ishinged to the transom 10, preferably by a piano-type hinge 17. The rearedge of the tab is turned upwardly at a transverse joint 18 parallelwith the front or leading edge of the tab so as to provide an upwardlyand rearwardly projecting angular extension which stiffens the tab andprovides for smoother flow of water over its rear edge. It will beapparent that due to the location of the hinge 17, the main body of thetab is, in effect, an extension of the bottom of the boat being coplanartherewith. The extension 19 extends upwardly and rearwardly from the tabso as to reduce turbulence at the rear edge of the tab. It will be notedthat the corners of the extension 19 are angled at 20 to further reduceturbulence.

To obtain lateral stability as the boat is passing through the water,each tab at each edge is provided with a depending stabilizing flange 21which also reinforces the body of the tab to make it rigid. It will benoted that each flange 21 angles downwardly from the hinge 17, where itsedge is substantially flush with the bottom 11, to its rear end 22, atthe joint 18, where it depends from the body of the tab a substantialdistance. Each depending flange 21 is in a vertical plane at a rightangle to the flat plane of the body of the trim tab.

Each of the tabs 13 and 14 is moved up or down positively to a selectedangular position by means of a double-acting hydraulic rarn or cylinderand piston unit 25. This unit 25 is pivotally connected to the transom10 at 23, on its outer vertical surface, and to the tab at 24, on itsupper surface rearwardly of the hinge axis 15 and adjacent the joint 18.The units 25 are preferably simultaneously activated by means of acombined motor and pump unit 26, located within the boat, preferablymounted on the inner surface of the transom, being connected to theunits 25 bythe necessary flexible conduit 27.

As the boat passes through the water, the proper attitude may beobtained by operating the switch 30 to select the proper angle on thetwo tabs 13 and 14 simultaneously. The switch 30 will be of thedouble-throw, double-pole type and will normally be held spring biasedinto off" ition. It will control a reversible motor 26a of the unit 2which Wlll, m

turn, control the reversible hydraulic pump 26b of that unit. Drivingthe motor 26a in one direction will actuate the rams 25 to swing thetabs 13 and 14 upwardly simultaneously and driving the motor in theother direction will actuate the rams 25 to swing them downwardly. Asthe boat is powered through the water, the water will pass beneath theflat bodies of the tabs 13 and 14, which will provide planing surfaces,and then over the rearwardly and upwardly angled extensions 19 with aminimum of turbulence. The flanges 21 projecting downwardly into thewater will create lateral stability. This is especially true at thecenter where water is passing through the space 16, between the twotabs, which space is lined up with the keel or centerline of the boatand acts on both adjacent flanges 21 to obtain a high degree of lateralstabilization. Positive displacement of the tabs up or down, asdescribed, may be obtained merely by moving the activating lever of theswitch 30 in the proper. direction. By using two separate tabs they canbe spaced apart as desired and angularly related relatively dependingupon the transverse contour of the bottom of the boat and the transom.

lclaim:

1. In combination with a power boat having a bottom and a transomconnected together at a joint at the stern of the boat; a pair oftrim-tabs hinged to the boat adjacent said joint and on opposite sidesof the centerline thereof;

said trim tabs comprising substantially flat body portions which arehinged at their forward edges to the boat and provide planing surfacesextending rearwardly from the boat bottom,

said tabs being spaced on each side of the centerline of the boat toprovide a space therebetween, said tabs having stabilizing flanges whichproject from the planing surfaces of the tabs at both the inner andouter edges of the respective tabs, each tab having an upwardly angledextension at its rear edge, and means for positively raising andlowering the hinged tabs, said means for positively raising and loweringthe tabs comprising a double-acting hydraulic ram connected between eachof said tabs and the transom of the boat, and means for activating bothof said rams simultaneously in the same direction, said activating meanscomprising a single selector switch movable from a normal off positioninto contact with either of two contacts, said contacts being connectedto a reversible electric motor which drives a reversible hydraulic pumpthat supplies actuating fluid to said rams.

1. In combination with a power boat having a bottom and a transomconnected together at a joint at the stern of the boat; a pair oftrim-tabs hinged to the boat adjacent said joint and on opposite sidesof the centerline thereof; said trim tabs comprising substantially flatbody portions which are hinged at their forward edges to the boat andprovide planing surfaces extending rearwardly from the boat bottom, saidtabs being spaced on each side of the centerline of the boat to providea space therebetween, said tabs having stabilizing flanges which projectfrom the planing surfaces of the tabs at both the inner and outer edgesof the respective tabs, each tab having an upwardly angled extension atits rear edge, and means for positively raising and lowering the hingedtabs, said means for positively raising and lowering the tabs comprisinga double-acting hydraulic ram connected between each of said tabs andthe transom of the boat, and means for activating both of said ramssimultaneously in the same direction, said activating means comprising asingle selector switch movable from a normal off position into contactwith either of two contacts, said contacts being connected to areversible electric motor which drives a reversible hydraulic pump thatsupplies actuating fluid to said rams.